Lost internet after installing AVG on several computers in a network

Hi there,

I'm really new here and need some help to fix this annoying issue. Here is the situation:

10 computers are connected to a network, I was installing AVG business edition on the first one, made sure access the networked storage, internet and email (outlook) were working, then duplicated the process of 5 other computers. After each successful setup I was running a whole computer scan just incase. By the time I was working on the 6th computer internet access to all the computers in the network was lost. What didnt make sense is that even the computers that didnt get the new AVG business addition lost connection. Yet when I plug any of the ethernet cables in the network to my personal laptop the internet works. I tried resetting TCP/IP and running winsockXPfix but nothing works, I also tried deactivating AVG, the firewall and even uninstalling AVG from 2 of the computers yet the internet is still lost on all the computers.

All the computers are running Windows XP SP3, Any help will be highly appreciated, thank you.